The present invention relates to an audio jack, and more particularly to a transfer switch for an audio jack consisting of a resilient contact and an engagement contact having a wiping contact therebetween for ensuring reliable contact.
Description of Prior Art
Multi-media devices are commonly attached to a computer, and audio jacks are popularly used in computers for providing the multi-media device with a connection port. An audio jack typically comprises an insulative housing, a plug receptacle projecting from the housing for receiving a complementary audio plug, and two transfer switches retained in the housing and downwardly extending therefrom for connecting to a printed circuit board. The normally closed transfer switch consists of a resilient contact for engaging with a mating contact of the complementary audio plug, and an engagement contact engaging with the resilient contact.
Among the problems which must be overcome for an audio jack to attain a satisfactory level of performance is that the audio jack must function in various environments, such as outdoors, where it is susceptible to environmental contaminants or where oxides may build up over time. The contaminants or oxides built up on a contact interface between the resilient contact and the engagement contact of the transfer switch may cause improper contact therebetween thereby interfering with signal transmission between the computer and the complementary audio plug. Since low electrical potential and current are applied to the audio jack, the energy present in power applications to burn off such contaminants or oxides is not available. Therefore, it is desirable to establish a wiping contact between the resilient contact and the engagement contact of the transfer switch to remove contaminants from the contact interface thereby ensuring signal transmission.